another test for too big type

Author: RalfJung

tests/compile-fail/slice-too-big.rs renamed to tests/compile-fail/too-big-slice.rs

@@ -0,0 +1,14 @@
+use std::mem;
+
+#[allow(unused)]
+struct MySlice {
+    prefix: u64,
+    tail: [u8],
+}
+
+fn main() { unsafe {
+    let ptr = Box::into_raw(Box::new(0u8));
+    let too_big = if cfg!(target_pointer_width = "64") { 1usize << 47 } else { 1usize << 31 };
+    // The slice part is actually not "too big", but together with the `prefix` field it is.
+    let _x: &MySlice = mem::transmute((ptr, too_big-1)); //~ ERROR: invalid reference metadata: total size is bigger than largest supported object
+} }